The present invention relates to a ballast stabilizer, and more particularly to such a ballast stabilizer which is water proof and dust proof and, which provides a stabilized path. The invention relates also to a method of fabricating such a ballast stabilizer.
In order to have the magnetic path of a ballast stabilizer be evenly distributed around the winding, the iron core may be arranged in the shape of the Chinese character , permitting the winding to be mounted around the center area. Further, in order to saturation of the magnetic path, air gaps may be provided at the silicon steel plates. FIG. 1 shows a ballast stabilizer according to the prior art, in which E-shaped silicon steel plates 51 and I-shaped silicon steel plates 52 are fastened together to hold a winding on the inside. The E-shaped silicon steel plates 51 each have a short middle support 511. When the E-shaped silicon steel plates 51 and I-shaped silicon steel plates 52 are fastened together, an air gap 53 exists between the short middle supports 511 and the I-shaped silicon steel plates 52 to stabilize the magnetic path. However, because the width of the air gap 53 is controlled by means of the depth in which the I-shaped silicon steel plates 52 are inserted, it is difficult to accurate control the width of the air gap 53 during the fabrication process. FIG. 2 shows another structure of ballast stabilizer according to the prior art, in which U-shaped silicon steel plates 54 and T-shaped silicon steel plates 55 are fastened together to hold a winding on the inside. When assembled, an air gap 56 is provided between the end of the T-shaped silicon steel plates 55 and the inside wall of the U-shaped silicon steel plates 54. This structure of ballast stabilizer cannot eliminate the aforesaid problem. FIGS. 3A and 3B show still another structure of ballast stabilizer according to the prior art. According to this structure of ballast stabilizer, a soft metal rod 57 is inserted in between the middle support 511 of the stack of E-shaped silicon steel plates 51 and the stack of I-shaped silicon steel plates 52, then the stack of E-shaped silicon steel plates 51 and the stack of I-shaped silicon steel plates 52 are compressed against each other, causing the soft metal rod 57 to be flattened, and therefore a gap is obtained between the middle support 511 of the stack of E-shaped silicon steel plates 51 and the stack of I-shaped silicon steel plates 52 to stabilize the magnetic path. This structure of ballast stabilizer is still not satisfactory in function. One drawback of this structure of ballast stabilizer is its poor insulative and water proof arrangement. Another drawback of this structure of ballast stabilizer is its complicated processing procedure and high manufacturing cost.